From: Alok Chauhan <[email protected]> In NACK error condition, I2C controller violates clock-to-data setup time before stop. In Software, because of this reset of controller is happening before I2C controller could complete STOP condition.
Added worst case delay of 1 ms (assuming lowest clock frequency will be 1 KHZ) before reset the controller in case of NACK error. Signed-off-by: Alok Chauhan <[email protected]> --- drivers/i2c/busses/i2c-tegra.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 6381604..b731499 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -517,6 +517,15 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) return 0; + /* + * In NACK error condition resetting of I2C controller happens + * before STOP condition is properly completed by I2C controller, + * so wait for worst case delay of 1 ms (assuming lowest clock + * frequency will be 1 KHz) to complete STOP condition. + */ + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) + mdelay(1); + tegra_i2c_init(i2c_dev); if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK) -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
